import time

class Clock(object):

    def __init__(self, hour=0, minute=0, second=0):

        self._hour = hour
        self._minute = minute
        self._second = second

    def run(self):

        self._second += 1

        if self._second >= 60:
            self._second = 0
            self._minute += 1

        if self._minute >= 60:
            self._minute = 0
            self._hour += 1

        if self._hour >= 24:
            self._hour = 0

    def show(self):

        return '%02d:%02d:%02d' % (self._hour, self._minute, self._second)

def main():
    clock = Clock(23, 59, 58)
    while True:
        print(clock.show())
        time.sleep(1)
        clock.run()

if __name__ == '__main__':
    main()